Information recording medium, recording/reproducing apparatus, and recording/reproducing method to distinguish between an original recording block and a replacement recording block

ABSTRACT

An information recording medium, and a recording/reproducing apparatus and a recording/reproducing method for the recording medium. Original data is sequentially updated by replacing an original recording block with one or more replacement recording blocks. A replacement recording block includes at least one of an original address field indicating a location of the original recording block or a previous address field indicating a location of an immediately previous recording block. Replacement information is effectively recovered in a system where a replacement for logical overwriting (LOW) occurs in either a spare area and a user data area by reference to the address fields in each replacement recording block.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/152,237, filed on Jun. 15, 2005, now allowed, which claims thebenefit of Korean Patent Application No. 10-2004-0060282, filed on Jul.30, 2004, in the Korean Intellectual Property Office, the disclosures ofwhich are incorporated herein by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Aspects of the present invention relate to information recording media,and more particularly, to an information recording medium, arecording/reproducing apparatus, and a recording/reproducing method, bywhich data replacement upon logical overwrite (LOW) occurring in a sparearea or in a user data area may be efficiently managed.

2. Description of the Related Art

Rewritable information recording media generally include a spare area ina portion of a data area to achieve defect management. In other words,when defective data is detected while user data is being recorded in auser data area (an area left by excluding the spare area from the dataarea) or while data recorded in the user data area is being reproduced,a replacement of the defective data is recorded in the spare area.

In write-once information recording media, such defect management methodis applied to logical overwrite (LOW). Logical overwrite is a techniquethat generates the same effect as the rewrite of data to write-onceinformation recording media. In other words, to update data alreadyrecorded in the user data area, the recorded data is treated asdefective data, and replacement data that replaces the recorded data isrecorded in the spare area. Accordingly, the logical address of the dataalready recorded in the user data area is still used as the logicaladdress of the replacement data, although the physical address of thereplacement data is different from the physical address of thealready-recorded data. Hence, a host can detect that the data alreadyrecorded in the user data area was overwritten, because the hostaccesses only a logical address. Thus, the host can easily manage thewrite-once information recording media.

However, a method of recording update data in an unrecorded area of auser data area instead of a spare area and providing replacementinformation (i.e., defect entry information) has been used to achieveLOW based on defect management to fully utilize the capacity of awrite-once information recording medium.

This recording of a replacement in the unrecorded area of the user dataarea to achieve LOW complicates the recovery of replacement datadestroyed by power failure or an error of replacement information. Wherean area in which a replacement of defective data or a replacement forLOW is recorded is limited to a spare area, a replacement block existsonly in the spare area. Hence, replacement data can be recovered bysearching only the separate spare area for replacement blocks. However,as a user data area is used as the area in which a replacement ofdefective data or a replacement for LOW is recorded, there appears aneed to classify the blocks recorded in a user area on an informationrecording medium into user blocks (original data block that is notreplaced by a new block) and replacement blocks. In addition, wherereplacement data is recorded in the user data area, predetermined rulesare needed to easily recover the replacement data.

In summary, where a replacement of user data for LOW cannot be recordedonly in a spare area but also in a user data area, user blocks cannot bedistinguished from replacement blocks due to the absence of a physicalboundary between a physical area in which the user blocks are recordedand a physical area in which the replacement blocks are recorded.Particularly, where a user block is replaced by a replacement block, andthe replacement block is replaced again, a final replacement blockcannot be identified. Finally, a drive system cannot distinguish betweena case where a replacement block is replaced again and a case where ablock is recorded in a physically unrecorded space in response to acommand to record data in a space that is physically recorded with databut logically unrecorded.

The above mentioned conventional problems will now be described withreference to FIGS. 1A through 1C. Referring to FIG. 1A, in case 1, a 1stupdate of original data A is recorded in track #1, and a 2nd update isrecorded in track #2. In case 2, a 1st update of original data A isrecorded in track #2, and a 2nd update is recorded in track #1. In case3, a 1st update of original data A is recorded in track #2, and a 2ndupdate is recorded in a spare area SA. In case 4, a 1st update oforiginal data A is recorded in a spare area, and a 2nd update isrecorded in track #2.

As shown in FIG. 1A, although only data A″ obtained by updating originaldata A twice exists in a logical space, a final update, namely, data A″,is recorded in different locations in a physical space in cases 1through 4.

Referring to FIG. 1B, in case 5, original data, data A, a first updateof the data A, data A′, and a second update of the data A, data A″, aresequentially recorded in a physical volume space of track #2 on a userdata area. Referring to FIG. 1C, in case 6, original data, data A, afirst update of the data A, data A′, and original data, data B, aresequentially recorded in a physical volume space of track #2 on a userdata area.

As shown in cases 5 and 6, although physical recording statuses in cases5 and 6 are the same, recording statuses of actual information recordingmediums in cases 5 and 6 are different. Thus, a block to be recordedneeds to include specific information so that a drive system candistinguish two different cases.

SUMMARY OF THE INVENTION

An aspect of the present invention provides an information recordingmedium, a recording/reproducing apparatus, and a recording/reproducingmethod, by which a replacement for logical overwriting (LOW) occurs inany of a spare area and a user data area to thereby improve theefficiency of data reproduction.

According to an aspect of the present invention, there is provided aninformation recording medium comprising: a user data area for recordinguser data; and a spare area for replacing a defect in the user dataarea, wherein: a replacement recording block that replaces an originalrecording block recorded in the user data area is recorded in the sparearea or an unrecorded area of the user data area, and a recording blockincludes at least one of an original address or a previous address, theoriginal address indicating a location of the original recording blockand the previous address indicating a location of an immediatelyprevious recording block.

The recording block may include a data part that contains original dataor replacement data and an additional information part that containsadditional information about the original data or the replacement data.The additional information part may contain at least one of the originaladdress or the previous address.

According to another aspect of the present invention, there is providedan information recording medium comprising: a user data area forrecording user data; and a spare area for replacing a defect in the userdata area, wherein: a replacement recording block that replaces anoriginal recording block recorded in the user data area is recorded inthe spare area or an unrecorded area of the user data area; and each ofthe original recording block and the replacement recording blockincludes identification information useable to determine whether eachrecording block is the original recording block or the replacementrecording block.

Each recording block may include a data part that contains original dataor replacement data and an additional information part that containsadditional information about the original data or the replacement data.The additional information part may contain the identificationinformation.

The additional information part may comprise at least one of an originaladdress field that indicates a location of the original recording blockor a previous address field that indicates a location of an immediatelyprevious recording block. The identification information may be aspecific identifier recorded in at least one of the original addressfield or the previous address field.

According to another aspect of the present invention, there is providedan information recording medium comprising: a user data area forrecording user data; and a spare area for replacing a defect detected inthe user data area, wherein: a replacement recording block that replacesan original recording block recorded in the user data area is recordedin the spare area or an unrecorded area of the user data area; and avalue of a physical address of the replacement recording block is alwayslarger than a value of a physical address of a recording block previousto the replacement recording block and a value of a physical address ofthe original recording block or always smaller than a value of aphysical address of a recording block previous to the replacementrecording block and a value of a physical address of the originalrecording block.

According to another aspect of the present invention, there is provideda recording/reproducing apparatus comprising: a write/read unit writingdata to and reading data from an information recording medium having auser data area for recording user data and a spare area for replacing adefect in the user data area, wherein a replacement recording block thatreplaces an original recording block recorded in the user data area isrecorded in the spare area or an unrecorded area of the user data area;and a controller controlling the write/read unit to write a recordingblock on the information recording medium, wherein the written recordingblock includes at least one of original address information indicating alocation of the original recording block or previous address informationindicating a location of an immediately previous recording block for theoriginal recording block.

According to another aspect of the present invention, there is provideda recording/reproducing apparatus comprising: a write/read unit writingdata to and reading data from an information recording medium having auser data area for recording user data and a spare area for replacing adefect in the user data area, wherein a replacement recording block thatreplaces an original recording block recorded in the user data area isrecorded in the spare area or an unrecorded area of the user data area;and a controller controlling the write/read unit to write a recordingblock on the information recording medium, wherein the written recordingblock includes identification information used to determine whether thewritten recording block is an original recording block or a replacementrecording block.

According to another aspect of the present invention, there is provideda recording/reproducing apparatus comprising: a write/read unit writingdata to and reading data from an information recording medium having auser data area for recording user data and a spare area for replacing adefect in the user data area, wherein a replacement recording block thatreplaces an original recording block recorded in the user data area isrecorded in the spare area or an unrecorded area of the user data area;and a controller controlling the write/read unit to write thereplacement recording block on the information recording medium so thata value of a physical address of the replacement recording block isalways larger than a value of a physical address of a previousreplacement recording block and a value of a physical address of theoriginal recording block or always smaller than a value of the physicaladdress of the previous replacement recording block and a value of thephysical address of the original recording block.

According to another aspect of the present invention, there is provideda recording/reproducing apparatus comprising: a write/read unit writingdata to and reading data from an information recording medium having auser data area for recording user data and a spare area for replacing adefect in the user data area, wherein a replacement recording block thatreplaces an original recording block recorded in the user data area isrecorded in the spare area or an unrecorded area of the user data area;and a controller recovering replacement information about the originalrecording block and the replacement recording block by referring to anoriginal address field of the replacement recording block that indicatesa location of the original recording block and a previous address fieldof the replacement recording block that indicates a location of animmediately previous recording block, which is replaced by thereplacement recording block.

According to another aspect of the present invention, there is provideda recording/reproducing method comprising: writing data to and readingdata from an information recording medium having a user data area forrecording user data and a spare area for replacing a defect in the userdata area, wherein a replacement recording block that replaces anoriginal recording block recorded in the user data area is recorded inthe spare area or an unrecorded area of the user data area; and writinga recording block on the information recording medium, wherein therecording block comprises at least one of an original address fieldindicating a location of the original recording block or a previousaddress field indicating a location of an immediately previous recordingblock.

According to another aspect of the present invention, there is provideda recording/reproducing method comprising: writing data to and readingdata from an information recording medium having a user data area forrecording user data and a spare area for replacing a defect in the userdata area, wherein a replacement recording block that replaces anoriginal recording block recorded in the user data area is recorded inthe spare area or an unrecorded area of the user data area; and writinga recording block on the information recording medium, wherein therecording block comprises identification information used to determinewhether the written recording block is an original recording block or areplacement recording block.

According to another aspect of the present invention, there is provideda recording/reproducing method comprising: writing data to and readingdata from an information recording medium having a user data area forrecording user data and a spare area for replacing a defect in the userdata area, wherein a replacement recording block that replaces anoriginal recording block recorded in the user data area is recorded inthe spare area or an unrecorded area of the user data area; and writinga replacement recording block on the information recording medium sothat a value of a physical address of the replacement recording block isalways larger than a value of a physical address of a recording blockprevious to the replacement recording block and a value a physicaladdress of the original recording block or always smaller than a valueof a physical address of the recording block previous to the replacementrecording block and the value the physical address of the originalrecording block.

According to another aspect of the present invention, there is provideda recording/reproducing method comprising: writing data to and readingdata from an information recording medium having a user data area forrecording user data and a spare area for replacing a defect in the userdata area, wherein a replacement recording block that replaces anoriginal recording block recorded in the user data area is recorded inthe spare area or an unrecorded area of the user data area; andrecovering replacement information about the original recording blockand the replacement recording block by referring to an original addressfield of the replacement recording block that indicates a location ofthe original recording block and a previous address field of therecording block that indicates a location of an immediately previousrecording block, which is replaced by the replacement recording block.

Where the immediately previous recording block is also the originalrecording block, the original address field and the previous addressfield may have a same value.

Where an expression of the form “at least one of A or B” is used herein,the expression should be interpreted as A or B or A and B.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be obviousfrom the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIGS. 1A through 1C are reference diagrams illustrating conventionalproblems;

FIG. 2 is a block diagram of a recording/reproducing apparatus accordingto an embodiment of the present invention;

FIG. 3 is a detailed block diagram of the recording/reproducingapparatus of FIG. 2;

FIG. 4 is a block diagram of a structure of an information recordingmedium used in the recording/reproducing apparatus of FIG. 2;

FIG. 5 is a block diagram of a data structure of a replacement entryshown in FIG. 4;

FIG. 6 is a block diagram of a structure of a block which isrecorded/reproduced as a unit in/from a user data area of theinformation recording medium shown in FIG. 4;

FIG. 7A illustrates a physical volume space of an information recordingmedium on which original and replacement blocks has been recorded,according to an embodiment of the present invention;

FIG. 7B illustrates a logical volume space of the information recordingmedium shown in FIG. 7

FIG. 8 is a block diagram of structures of replacement entries producedbased on the recorded blocks illustrated in FIG. 7A;

FIGS. 9A-9D are block diagram of structures of replacement entriesrecovered based on the recorded blocks illustrated in FIG. 7A;

FIG. 10 is a flowchart illustrating a method of recording data accordingto an embodiment of the present invention; and

FIG. 11 is a flowchart illustrating a method of recovering a replacemententry according to the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below in order to explain thepresent invention by referring to the figures.

FIG. 2 is a block diagram of a recording/reproducing apparatus 200according to an embodiment of the present invention. Referring to FIG.2, the recording/reproducing apparatus 200 includes a write/read unit220 and a controller 210. The write/read unit 220 writes data to aninformation recording medium 400, under control of the controller 210and reads out written data to reproduce the written data. The controller210 controls the write/read unit 220 to write/read data in a recordingunit block or obtains effective data by processing data read by thewrite/read unit 220. The recording/reproducing apparatus 200 asdisclosed herein includes features for recording and reproducing;however, as will be appreciated by persons skilled in the art, someaspects of the invention relate only to recording information and otheraspects of the invention relate only to reproducing information. Thus,as the context may imply, recording/reproducing includes an apparatusfor recording, an apparatus for reproducing or an apparatus forrecording and reproducing information.

Upon writing, the controller 210 controls the write/read unit 220 towrite data by performing logical overwriting (LOW) according to acommand of a host or under the control of the recording/reproducingapparatus 200. LOW denotes a technique in which data recorded in a userdata area of a write-once recording medium is updated by recordingreplacement data in a spare area or in an unrecorded area of the userdata area, and addresses of the original data and the replacement dataare managed so that a host cannot recognize any change to a logicaladdress. This management is achieved by writing a replacement entry andrecording the replacement entry on the information recording medium. Asdescribed above, the controller 210 controls the write/read unit 220 towrite replacement data to a spare area or to an unrecorded area of auser data area according to LOW. The controller 210 generates a blockincluding a data part based on a write command of a host and anadditional information part with a previous address field and anoriginal address field of a block to be replaced and controls thewrite/read unit 220 to write the generated block to the informationrecording medium 400. Where a replacement entry having replacementinformation is not reproduced before recording or reproducing data, thecontroller 210 recovers the replacement entry using values of theprevious address field and the original address field included in theadditional information part of the block.

FIG. 3 is a detailed block diagram of the recording/reproducingapparatus 200 of FIG. 2. Referring to FIG. 3, the recording/reproducingapparatus 200, i.e., a disc drive, includes a pickup 250, which servesas the write/read unit 220. The information storage medium 400 isinstalled to be accessed by the pickup 250. The recording/reproducingapparatus 200 includes a host interface (I/F) 211, a digital signalprocessor (DSP) 212, an RF AMP 213, a servo 214, and a system controller215, which serve as the controller 210.

Where data is to be written to the information storage medium 400, thehost I/F 211 receives the data to be written and a write commandtogether with information about a logical address of the to-be-writtendata from the host 240 and transmits the received data, command, andinformation to the system controller 215.

The system controller 215 receives the write command from the host I/F211 and performs an initialization necessary for the writing. Inparticular, in a case other than where data is overwritten to a recordedarea, the system controller 215 controls the pickup 250 to write thedata to an address indicated by the write command. On the other hand,when data is to be overwritten to a recorded area, the system controller215 controls the pickup 250 to write the update data to an unrecordedarea of a user data area using linear replacement, generate a defectentry indicating a status of replacement based on LOW, and write thedefect entry to a temporary defect information area of the informationrecording medium 400. Since data is written on the information recordingmedium 400 in a recording unit block, the system controller 215generates a block by determining values of a previous address field andan original address field with reference to a not-yet-replaced block andreplacement entry and controls the pickup 250 to write the block to theinformation recording medium 400.

The DSP 212 adds additional data, such as, parity, to the to-be-writtendata received from the host I/F 211 to achieve error correction,performs ECC (error correction code) encoding on the resultantto-be-written data to produce an error-corrected block, namely, an ECCblock, and modulates the ECC block in a predetermined scheme. The RF AMP213 converts data output from the DSP 212 into an RF signal. The pickup250 receives the RF signal from the RF AMP 213 and writes the RF signalto the information storage medium 400. The servo 214 receives a commandnecessary for servo control from the system controller 215 andservo-controls the pickup 250.

Where data is to be read from the information storage medium, the hostI/F 211 receives a read command from the host 240. The system controller215 performs an initialization necessary for the reading. In particular,the system controller 215 converts a logical address indicated by theread command into a physical address and searches for a replacementaddress from the replacement entry on the basis of the convertedphysical address. If the replacement entry cannot be read out, thesystem controller 215 recovers the replacement entry. The replacemententry is recovered by referring to original address information andprevious address information included in a recorded block. The recoveryof the replacement entry will be described in greater detail below.

The pickup 250 radiates a laser beam onto the information storage medium400, receives a laser beam reflected by the information storage medium400, and outputs an optical signal obtained from the received laserbeam. The RF AMP 213 converts the optical signal received from thepickup 250 into the RF signal and provides modulated data extracted fromthe RF signal to the DSP 212 and a servo control signal extracted fromthe RF signal to the servo 214. The DSP 212 demodulates the modulateddata, performs ECC on the demodulated data, and outputs resultant data.

The servo 214 receives the servo signal from the RF AMP 213 and thecommand necessary for servo control from the system controller 215 andservo-controls the pickup 250. The host I/F 211 transmits the dataoutput from the DSP 212 to the host 240.

FIG. 4 is a block diagram of a structure of the information recordingmedium 400 where the information recording medium is embodied as a disc.Referring to FIG. 4, the information recording medium 400 includes alead-in area 410, a data area 420, and a lead-out area 430.

The lead-in area 410 includes a second disc management area 411, atemporary disc management area (TDMA) 412, a first disc management area413, a first spare area 421, a user data area 422, a second spare area423, a third disc management area 421 and a fourth disc management area432.

The TDMA 412 denotes an area for recording information used for bothtemporary defect management and temporary information recording mediummanagement which are required to manage a write-once informationrecording medium. The TDMA 412 includes a temporary defect list (TDFL)414 as temporary defect information, a temporary disc definitionstructure (TDDS) 415 as temporary defect management information, and aspace bit map (SBM) 416.

The TDFL 414 denotes information about a defect and includes informationabout a location of defective data and information about a location ofreplacement data of the defective data. In particular, the TDFL 414includes a replacement entry 417.

FIG. 5 illustrates a data structure of the replacement entry 417.Referring to FIG. 5, the replacement entry 417 includes an originaladdress 418 and a replacement address 419. The original address 418denotes a start sector address of an original block, and the replacementaddress 419 denotes a start sector address of a replacement block.Because replacement is performed in units of a block, which is a unit inwhich data is recorded/reproduced, a status of the replacement isrepresented as a block.

Referring again to FIG. 4, the TDDS 415 stores location pointers of thetemporary defect information 414, the SBM 416, and a drive area (notshown), information about a location and size of a spare area allocatedupon initialization, write-protection information, information about alocation and size of a temporary defect management area (not shown)allocated in the data area 420, information about a user data area 422,information about locations on first and second spare areas 421 and 423where replacement data can be written, information about an address offinal data written in the user data area 422, etc.

The SBM 416 denotes a map in which recorded clusters and unrecordedclusters of the user data area 422 are represented as different bitvalues. The SBM 416 is used when the user data area 422 is used in arandom recording mode. On the other hand, when the user data area 422 isused in a sequential recording mode, recording management information inwhich a status of an information recording medium on which data isrecorded is represented as entry information is used instead of the SBM416.

The first disc management area 413, the second disc management area 411,the third disc management area 431, and the fourth disc management area432 are allocated to record final temporary management information whena write-once information recording medium is finalized.

The data area 420 includes the first spare area 421, the user data area422, and the second spare area 423 that are sequentially arranged. Thefirst and second spare areas 421 and 423 are allocated to recordreplacement data, that is, data that replaces data recorded in the userdata area 422. The first and second space areas 421 and 423 may storereplacement data that replaces defective data or replacement datanecessary for LOW, namely, replacement data that replaces user data.

The user data area 422 denotes an area for recording user data. Inparticular, replacement data that replaces the user data according toLOW is not only recorded in the spare area 421 or 423 but also in theuser data area 422. A block which is recorded as a unit is written tothe user data area 422.

A recording unit block 500 according to an embodiment of the presentinvention is shown in FIG. 6. Referring to FIG. 6, the recording unitblock 500 includes a data part 510 and an additional information part520. The data part 510 is user data. If the recording unit block 500 isan original block, the data part 510 is original data that is initiallyrecorded. If the recording unit block 500 is a replacement block, thedata part 510 is replacement data.

The additional information part 520 includes additional informationabout the original data or the replacement data. As shown in FIG. 6, theadditional information part 520 includes a previous address field 521and an original address field 522. The original address field 522records an address representing a location of the original block. Theprevious address field 521 records an address representing a location ofan immediately previous block, which is replaced by the recording unitblock 500. The additional information part 520 may have an errorcorrection structure different from that of the data part 510.

FIG. 7A illustrates a structure of an information recording medium onwhich a block which is recorded/reproduced as a unit has been recorded.More specifically, a status of the information recording medium on whichaddress information is stored in the previous address field and theoriginal address field of a block if the block is comprised of onesector is illustrated in FIG. 7A. In a general optical system, a hostmanages data in units of a sector (2048 bytes), and a drive systemmanages data in units of 16 or 32 sectors on an information recordingmedium.

Referring to FIG. 7A, when a host commands a drive system to write dataA to Logical Serial Number “a” (LSN a) to record data A, the drivesystem writes data A to Physical Serial Number “a” (PSN a) on aninformation recording medium, which corresponds to the LSN a. At thistime, both values of a previous address field and an original addressfield included in a block are set to be 0 to indicate that the block isan original block. A block that is initially recorded and does notreplace any block. In this way, an original block may be distinguishedfrom a replacement block.

Other methods can be used to distinguish the replacement block from theoriginal block. For example, the value of the previous address field orthe value of the original address field may be set to be a specificidentifier. Also, the value of the previous address field and the valueof the original address field may be set to a same value to indicatethat the block includes original data. The same value may be a valueindicating the PSN where the original data is recorded.

A method of recording a replacement block will now be described. Toperform a 1st update of data A with data A′ through LOW, the hostcommands the drive system to write data A′ to LSN a, and the drivesystem writes the data A′ to an unrecorded area PSN a−1 on theinformation recording medium by determining that the PSN a on theinformation recording medium corresponding to the LSN a has already beenrecorded with data. As shown in FIG. 8, the drive system generates areplacement entry #1 to indicate that the PSN a has been replaced by thePSN a−1. FIG. 8 shows the replacement entry #1 in which the PSN a is setas an original address and the PSN a−1 is set as a replacement address.Referring again to FIG. 7A, values of a previous address field 701 andan original address field 703 in the replacement block having the dataA′ and recorded in the PSN a−1 are both set to PSN a to indicate thatthe replacement block recorded at PSN a−1 replaces the block recorded atPSN a and that a physical address (i.e., an original address)corresponding to the logical address of data A′ recorded at PSN a−1 isPSN a.

Thereafter, to perform a 2nd update of data A, i.e., update data A′ withdata A″ according to LOW, the host commands the drive system to writedata A″ to LSN a, and the drive system writes the data A″ to anunrecorded area PSN a+1 on the information recording medium bydetermining that the PSN a on the information recording mediumcorresponding to the LSN a has already been recorded with data anddetermining from the replacement entry #1 that PSN a has been replacedby PSN a−1. Also, the drive system changes replacement entry #1 toindicate that PSN a has been replaced by PSN a+1, as shown in FIG. 8.Referring again to FIG. 7A, a value of the previous address field 701 inthe replacement block having the data A″ and recorded at PSN a+1 is setto PSN a−1 to indicate that the replacement block replaces the blockrecorded at PSN a−1. A value of an original address field 703 in thereplacement block having the data A″ and recorded at PSN a+1 is set toPSN a to indicate that a physical address (i.e., an original address)corresponding to the logical address of data A″ recorded at PSN a+1 isPSN a.

In a case where data B is to be written to the information recordingmedium after the 2nd update of data A with data A″, the host commandsthe drive system to write the data B to LSN a+1, and the drive systemwrites the data B to an unrecorded area PSN a+2 on the informationrecording medium by determining that the PSN a+1 on the informationrecording medium corresponding to the LSN a+1 has already been recordedwith data, i.e., the data A″. Also, the drive system generatesreplacement entry #2 to indicate that PSN a+1 has been replaced by PSNa+2, thus LSN a+1 corresponds to PSN a+2, as shown in FIG. 8. Referringagain to FIG. 7A, values of the previous address field 701 and theoriginal address field 703 in the block including the data B andrecorded at PSN a+2 are both set to PSN a+1 to indicate that the blockrecorded at PSN a+2 includes original data, i.e., data B (althoughsubsequently recorded) and that the logical address of the data Brecorded at PSN a+2 is PSN a+1.

Thereafter, to update data B with data B′ according to LOW, the hostcommands the drive system to write data B′ to LSN a+1, and the drivesystem writes the data B′ to an unrecorded area PSN a+3 on theinformation recording medium by determining that the PSN a+1 on theinformation recording medium corresponding to the LSN a+1 has alreadybeen recorded with data (i.e., data A″) and determining from thereplacement entry #2 that original address PSN a+1 has been replaced byPSN a+2. Also, the drive system changes replacement entry #2 to indicatethat PSN a+1 has been replaced by PSN a+3. FIG. 8. also shows thechanged replacement entry #2 in which the replacement address is PSNa+3. Referring again to FIG. 7A, a value of the previous address field701 in the replacement block including data B′ and recorded at PSN a+3is set to PSN a+2 to indicate that the replacement block replaces theblock recorded at PSN a+2. A value of an original address field in thereplacement block including the data B′ and recorded at PSN a+2 is setto PSN a+1 to indicate that a physical address (i.e., an originaladdress) corresponding to the logical address of data B′ recorded at PSNa+3 is PSN a+1. A resulting logical volume space 703 generated byreplacing the data A with the data A′ and then with the data A″ andsubsequently recording the data B and then replacing the data B with thedata B′ is shown in FIG. 7B. That is, data A″ corresponds to LSN a andthe data B′ corresponds to LSN a+1.

A method of recovering a replacement entry will now be described. If aninformation recording medium on which data is written as described aboveis loaded on a drive system, and the drive system fails to obtain afinal TDFL from a temporary defect management area of a lead-in orlead-out area of the information recording medium, the drive system mustrecover at least a replacement entry, which indicates a status of theinformation recording medium on which replacement data required upondefect generation or LOW has been recorded, among the TDFL. Thereplacement entry is recovered using values of a previous address fieldand an original address field included in an additional information partof a block recorded on the information recording medium. Thisreplacement entry recovery will now be described with reference to FIGS.7A through 9.

First, assuming, for example, values as shown in FIG. 7A, the drivesystem reads out a block recorded at PSN a−1 and determines from a valuePSN a set in the previous address field 701 of the read-out block thatPSN a−1 previously replaced PSN a and from a value PSN a set in theoriginal address field 703 of the read-out block that data A′ recordedat PSN a−1 has a logical address corresponding to PSN a. According tothis determination, the drive system recovers replacement entry #1 ofFIG. 9A, which indicates a status of the information recording medium onwhich a block recorded at PSN a has been replaced by a block recorded atPSN a−1.

Then, the drive system reads out a block recorded at PSN a anddetermines from a value “0” set in both the previous address field 701and the original address field 703 of the read-out block PSN a that theread-out block PSN a is an original block, namely, a non-replaced block.

Thereafter, the drive system reads out a block recorded at PSN a+1 anddetermines from a value PSN a−1 set in the previous address field 701 ofthe read-out block PSN a+1 that the read-out block PSN a+1 has replacedthe block recorded at PSN a−1 and from a value PSN a set in an originaladdress field 703 of the read-out block PSN a+1 that user data includedin the read-out block PSN a+1 has a logical address corresponding to PSNa. Since the drive system can determine from the replacement entry #1 ofFIG.9A that the block with address PSN a has been replaced by the blockwith address PSN a−1 and the block with address PSN a−1 has beenreplaced by the block with address PSN a+1, the drive system changes thereplacement address of the replacement entry #1 of FIG. 9A from PSN a−1to PSN a+1 to recover replacement entry #1 of FIG. 9B.

Then, the drive system reads out a block recorded at PSN a+2 anddetermines from a value PSN a+1 set in the previous address field 701 ofthe read-out block that the read-out block PSN a+2 has replaced theblock with address PSN a+1 and from a value PSN a+1 set in the originaladdress field 703 of the read-out block PSN a+2 that user data includedin the read-out block PSN a+2 has a logical address corresponding to PSNa+1. According to this determination, the drive system recoversreplacement entry #2 of FIG. 9C, which indicates a status of theinformation recording medium on which PSN a+1 has been replaced by PSNa+2.

Thereafter, the drive system reads out a block recorded at PSN a+3 anddetermines from a value PSN a+2 set in the previous address field 701 ofthe read-out block that the read-out block PSN a+3 has replaced theblock recorded at PSN a+2 and from a value PSN a+1 set in an originaladdress field 703 of the read-out block that user data included in theread-out block PSN a+3 has a logical address corresponding to PSN a+1.Since the drive system can determine from the replacement entry #2 ofFIG.9C that the block with address PSN a+1 has been replaced by theblock with address PSN a+2 and can determine from the value PSN a+2 readout from the block PSN a+3 the block with address PSN a+2 has beenreplaced by the block with address PSN a+3, the drive system changes thereplacement address of the replacement entry #2 of FIG. 9C from PSN a+2to PSN a+3 to recover replacement entry #2 of FIG. 9D.

As described above, exact replacement entry #1 and exact replacemententry #2 are recoverable using a previous address field and an originaladdress field included in an additional information part of a block.More specifically, in a replacement entry recovering method according toan embodiment of the present invention, the location of a finalreplacement block is recognizable from values set in the previousaddress fields of reproduced blocks having original address fields inwhich an identical value is stored, so that correct replacement entriesfor the blocks are recoverable. In other words, an original addressfield of a reproduced block provides a physical address of an originalblock to be set as an original address of a replacement entry for thereproduced block, and a previous address field of the reproduced blockprovides a physical address of a final replacement block of the originalblock to be set as a replacement address of the replacement entry.

In the example shown in FIG. 7A, it can be seen that if a recorded blockonly includes the original address field 703, a replacement entry forthe recorded block cannot be properly recovered. However, thereplacement entry may be properly recovered using only the originaladdress field 703 of a reproduced block by applying restrictions to amethod of recording a replacement block. Where replacement blocks arerecorded in a predetermined sequence, the replacement entry may berecovered using only values recorded in the original address field 703by reference to the original address field 703 values and thepredetermined sequence. That is, where the PSN of a later block in thesequence has a value recorded in the original address field 703 whichcorresponds to the PSN of an earlier block in the sequence, it may bedetermined that the later block in the sequence replaces the earlierblock in the sequence. Thus, the PSN of a latest block in the sequencehaving a value corresponding to the PSN of the earlier block in thesequence recorded in the original address field 703 is a finalreplacement block for the earlier block in the sequence.

For example, if replacement is performed under a rule that a physicaladdress of a current replacement block is always greater than a physicaladdress of each previous replacement block and a physical address of anoriginal block, it can be determined from a history of replacementcontained in an arrangement of physical addresses that a replacementblock having a highest physical address in a sequence of replacementblocks is the final replacement block.

As another example, if replacement is performed under a rule that aphysical address of a current replacement block is always smaller than aphysical address of each previous replacement block and a physicaladdress of an original block, it can be determined from a history ofreplacement contained in an arrangement of physical addresses that areplacement block having a lowest physical address in a sequence ofreplacement blocks is the final replacement block.

If only the previous address field 701 is included in a block in thecase of FIG. 7A, a wrong replacement entry is recovered by recognizingthat a block recorded at PSN a has been replaced by a block recorded atPSN a+3. However, if data B were allowed to be recorded at LSN a+2instead of LSN a+1 (that is, if writing of data to an area that isrecorded with data in a physical space although being unrecorded in alogical space is prohibited or if a drive system informs a host of anerror on receipt of a command to write data to such an area describedabove), data B could be recorded at PSN a+2 corresponding to LSN a+2,and data B′ could be recorded at PSN a+3 according to LOW. As describedabove, if writing of data to an area that is recorded with data in aphysical space although being unrecorded in a logical space isprohibited or if a drive system informs a host of an error on receipt ofa command to write data to such an area described above, problems asshown in FIGS. 1B and 1C can be solved. Only in this case, even whereonly a previous address field is used as address information to recovera replacement entry, the replacement entry may be correctly recovered.

FIG. 10 is a flowchart illustrating a method of recording data accordingto an embodiment of the present invention. In operation 1001, a drivesystem receives a data write command from a host. Since the host onlyoperates with logical addresses, the host provides to the drive system alogical address where data is to be recorded.

In operation 1002, the drive system converts a logical address indicatedby the data write command into a physical address. In operation 1003,the drive system determines whether the physical address is unrecorded.Where the physical address is unrecorded, the drive system determinesthat data indicated by the data write command is not replacement databut new user data, and thus a previous address field and an originaladdress field are both set to be 0, in operation 1004.

When it is determined that the physical address is recorded, the drivesystem determines that data indicated by the data write command denotesreplacement data with which data already recorded in the recordedphysical address is to be updated, and thus a replacement entry for theoriginal data is searched for, in operation 1005.

Where no replacement entries are found, values of a previous addressfield and an original address field of the replacement data, that is, areplacement block to be currently recorded, are both set to be thephysical address corresponding to the logical address indicated by thedata write command, in operation 1006. The physical address indicates alocation where the original user data has been recorded. In operation1007, a replacement entry including an original address and areplacement address is generated. The original address identifies thephysical address of the original user data, and the replacement addressidentifies a physical address in which the current replacement block isto be recorded.

Where the replacement entry is found, it may be determined whether theoriginal data has been preciously replaced, and accordingly, the valuesof the previous address field and the original address field of thecurrent replacement block are determined with reference to the foundreplacement entry. In other words, in operation 1008, the previousaddress field of the current replacement block is set to be areplacement address of the found replacement entry, and the originaladdress field of the current replacement block is set to be the originaladdress of the found replacement entry. In operation 1009, thereplacement address of the found replacement entry is changed from thephysical address of the previous replacement block to the physicaladdress of the current replacement block.

In operation 1010, the current replacement block is generated byincluding the data indicated by the data write command of the host andadditional information (the previous address field and the originaladdress field) and recorded at the replacement address on an informationrecording medium. In operation 1011, the newly produced replacemententry or the changed replacement entry is recorded in a lead-in orlead-out area of the information recording medium.

FIG. 11 is a flowchart illustrating a method of recovering a replacemententry according to an aspect of the present invention. First, inoperation 1110, a block recorded in a user data area is reproduced, andinformation contained in a previous address field and an originaladdress field is acquired from an additional information part of thereproduced block.

In operation 1120, a replacement entry including a replacement addressand an original address is recovered. A physical address of a firstreproduced block is set as the replacement address of the replacemententry, and the value of the original address field included in theadditional information part of the first reproduced block is set as theoriginal address of the replacement entry.

In operation 1130, a second block next to the first reproduced block andrecorded in the user data area is reproduced, and information containedin a previous address field and an original address field is acquiredfrom the additional information part of the second block. In operation1140, it is determined whether the original address of the recoveredreplacement entry is consistent with the information contained in theoriginal address field of the second reproduced block.

If the original address of the recovered replacement entry is differentfrom the information contained in the original address field of thesecond reproduced block, the second reproduced block is new user datadifferent from user data of the first reproduced block. Hence, themethod goes back to operation 1120 to recover a replacement entry forthe second block reproduced in operation 1130.

If the original address of the recovered replacement entry is identicalto the information contained in the original address field of the secondreproduced block, the second block reproduced in operation 1130 is notnew user data but replacement data that replaces the same user data asthe user data replaced by the first reproduced block. Hence, inoperation 1150, the replacement address of the recovered replacemententry is changed to a physical address of the next reproduced block.

Then, in operation 1160, it is determined whether a block to be furtherreproduced exists. If a block to be further reproduced exists, themethod goes back to operation 1110 to reproduce the remaining block. Ifno blocks to be further reproduced exist, the method is concluded.

According to an aspect of the present invention as described above,replacement information can be effectively recovered in a system where areplacement for LOW occurs in a spare area or in a user data area. Thus,the efficiency of data reproduction improves.

A data recording/reproducing method and a replacement entry recoveringmethod as described above may also be embodied as computer readablecodes on a computer readable recording medium. The computer readablerecording medium is any data storage device that can store data whichcan be thereafter read by a computer system. Examples of the computerreadable recording medium include read-only memory (ROM), random-accessmemory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical datastorage devices, and carrier waves (such as data transmission throughthe Internet). The computer readable recording medium can also bedistributed over network coupled computer systems so that the computerreadable code is stored and executed in a distributed fashion. Also,functional programs, codes, and code segments for accomplishing the datarecording/reproducing method and the replacement entry recovering methodmay be construed by programmers skilled in the art of informationrecording.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in this embodiment without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1. An information recording medium, wherein the second recording unitblock is selected in a user data area of the information recordingmedium in response to a command to record second data in the firstrecording unit block in which first data already has been recorded; thesecond recording unit block has a logical address identical to a logicaladdress of the first recording unit block; and the defect list entrycomprises: physical address information of the first recording unitblock; and physical address information of the second recording unitblock.
 2. A recording/reproducing apparatus, wherein the secondrecording unit block is selected in a user data area of the informationrecording medium in response to a command to record second data in thefirst recording unit block in which first data already has beenrecorded; the second recording unit block has a logical addressidentical to a logical address of the first recording unit block; andthe defect list entry comprises: physical address information of thefirst recording unit block; and physical address information of thesecond recording unit block.
 3. A reproducing apparatus, wherein thesecond recording unit block is selected in a user data area of theinformation recording medium in response to a command to record seconddata in the first recording unit block in which first data already hasbeen recorded; the second recording unit block has a logical addressidentical to a logical address of the first recording unit block; andthe defect list entry comprises: physical address information of thefirst recording unit block; and physical address information of thesecond recording unit block.
 4. A recording method, wherein the secondrecording unit block is selected in a user data area of the informationrecording medium in response to a command to record second data in thefirst recording unit block in which first data already has beenrecorded; the second recording unit block has a logical addressidentical to a logical address of the first recording unit block; andthe defect list entry comprises: physical address information of thefirst recording unit block; and physical address information of thesecond recording unit block.
 5. A reproducing method, wherein the secondrecording unit block is selected in a user data area of the informationrecording medium in response to a command to record second data in thefirst recording unit block in which first data already has beenrecorded; the second recording unit block has a logical addressidentical to a logical address of the first recording unit block; andthe defect list entry comprises: physical address information of thefirst recording unit block; and physical address information of thesecond recording unit block.